What size should a YouTube thumbnail be?

The usual recommendation is 1280 × 720 pixels with a 16:9 aspect ratio. This previewer checks those dimensions and warns when the ratio or size is different, but it does not crop or stretch your image.

Does this YouTube thumbnail tool upload my image?

No. The image is read and previewed in your browser using a temporary local object URL. It is not sent to a Brand Armor AI server or an external API.

Which YouTube layouts can I preview?

You can switch between search results, the home feed, a sidebar or Up next-style row, and a mobile layout. These are practical visual checks rather than exact replicas of every YouTube experiment or responsive state.

Can this tool predict thumbnail CTR or YouTube rankings?

No. It helps you check composition, contrast, text legibility, and dimensions. Click-through rate and rankings depend on the audience, topic, title, distribution, and actual viewer behavior, so use YouTube Analytics for performance decisions.

How should I design text on a YouTube thumbnail?

Use one clear message, a strong focal point, high contrast, and type that remains readable when the thumbnail is small. Previewing the sidebar and mobile modes is especially useful for catching text that only works at full desktop size.

Free tools

Free YouTube Thumbnail Preview Tool

Upload a thumbnail locally, test its legibility across common YouTube surfaces, and check the 16:9 dimensions without sending your image to a server.

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Tool 01

YouTube Thumbnail Preview Tool

Preview the same thumbnail in search, home feed, sidebar, and mobile layouts. Check the dimensions without uploading the image.

Add your thumbnail

Everything stays in this browser. Your image is never uploaded.

Drop an image here

PNG, JPEG, WebP, or another browser-readable image up to 20 MB

Video title

Channel

Views

Published

Preview at a glance

See how the same creative reads in common YouTube surfaces.

Search results

Upload a thumbnail to preview it here

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How to Make Your Website More Visible in AI Search

Brand Armor AI

24K views · 2 days ago

Local preview

Visual QA helps with legibility; it does not predict ranking or click-through rate.

How it works

YouTube Thumbnail Preview Tool: methodology and worked example

How this tool computes its result

The previewer reads an image file locally, measures its natural width and height, and creates a temporary browser object URL for the visual mockups. The same image is rendered with object-fit: cover inside search, home-feed, sidebar, and mobile layouts so you can judge how quickly the composition and text read at smaller sizes. No image is sent to an API. The dimension check compares the file with the usual 1280 × 720 recommendation and flags non-16:9 files without cropping or stretching them.

Worked example

Upload a 1280 × 720 PNG, then switch between Search, Home feed, Sidebar, and Mobile. The image receives the recommended-dimensions check and the title, channel, views, and age fields update around the same creative. If you upload a 900 × 900 square file, the preview still shows the original artwork but warns that the ratio is not the normal 16:9 thumbnail shape; it does not silently crop away the edges.

When not to use this tool

This is a visual QA tool, not a CTR predictor, ranking checker, or YouTube A/B testing system. It cannot tell whether a thumbnail will win a particular audience, and YouTube can change layouts or apply its own responsive cropping. Use actual audience experiments and YouTube Analytics for performance decisions.

Common mistakes

- Designing only for the full-size desktop thumbnail and missing that small text becomes unreadable in search, recommendations, or mobile feeds.
- Uploading a screenshot that already contains browser or YouTube interface elements instead of the clean thumbnail artwork.
- Assuming a 16:9 preview guarantees performance. Contrast, one clear focal point, and a readable idea still matter more than matching a dimension alone.

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